Method and device for allocating resource units using leftover tones in wireless LAN

ABSTRACT

Disclosed are a method and a device for allocating resource units using leftover tones in a wireless LAN. The method for allocating resource units using leftover tones in a wireless LAN may comprise the steps of: an AP generating PPDUs to be transmitted to a plurality of STAs; and the AP transmitting the PPDUs to the plurality of STAs on all frequency bands, wherein the PPDUs are transmitted from each of a plurality of resource unit sets respectively allocated to each of the plurality of STAs, wherein each of the plurality of resource unit sets includes a first resource unit set and a second resource unit set, wherein the first resource unit set includes at least one resource unit, the second resource unit set includes one tone design resource unit, and wherein the tone design resource unit may include at least one other resource unit and at least one additional tone unit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International ApplicationNo. PCT/KR2015/012671, filed on Nov. 24, 2015, which claims priorityunder 35 U.S.C. 119(e) to U.S. Provisional Application No. 62/083,320,filed on Nov. 24, 2014, 62/083,888, filed on Nov. 24, 2014, 62/090,368,filed on Dec. 11, 2014, and 62/091,638, filed on Dec. 15, 2014, all ofwhich are hereby expressly incorporated by reference into the presentapplication.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to wireless communication and, mostparticularly, to a method and device for allocating resource units usingleftover tones in a wireless LAN.

Related Art

Discussion for a next-generation wireless local area network (WLAN) isin progress. In the next-generation WLAN, an object is to 1) improve aninstitute of electronic and electronics engineers (IEEE) 802.11 physical(PHY) layer and a medium access control (MAC) layer in bands of 2.4 GHzand 5 GHz, 2) increase spectrum efficiency and area throughput, 3)improve performance in actual indoor and outdoor environments such as anenvironment in which an interference source exists, a denseheterogeneous network environment, and an environment in which a highuser load exists, and the like.

An environment which is primarily considered in the next-generation WLANis a dense environment in which access points (APs) and stations (STAs)are a lot and under the dense environment, improvement of the spectrumefficiency and the area throughput is discussed. Further, in thenext-generation WLAN, in addition to the indoor environment, in theoutdoor environment which is not considerably considered in the existingWLAN, substantial performance improvement is concerned.

In detail, scenarios such as wireless office, smart home, stadium,Hotspot, and building/apartment are largely concerned in thenext-generation WLAN and discussion about improvement of systemperformance in a dense environment in which the APs and the STAs are alot is performed based on the corresponding scenarios.

In the next-generation WLAN, improvement of system performance in anoverlapping basic service set (OBSS) environment and improvement ofoutdoor environment performance, and cellular offloading are anticipatedto be actively discussed rather than improvement of single linkperformance in one basic service set (BSS). Directionality of thenext-generation means that the next-generation WLAN gradually has atechnical scope similar to mobile communication. When a situation isconsidered, in which the mobile communication and the WLAN technologyhave been discussed in a small cell and a direct-to-direct (D2D)communication area in recent years, technical and business convergenceof the next-generation WLAN and the mobile communication is predicted tobe further active.

SUMMARY OF THE INVENTION Technical Objects

An object of the present invention is to provide a method for allocatingresource units using leftover tones in a wireless LAN.

Another object of the present invention is to provide a device forallocating resource units using leftover tones in a wireless LAN.

Technical Solutions

In order to achieve the above-described technical object of the presentinvention, according to an aspect of the present invention, a method forallocating resource units using leftover tones in a wireless LAN mayinclude the steps of generating, by an access point (AP), a PHY layerprotocol data unit (PPDU) that is to be transmitted to a plurality ofstations (STAs), and transmitting, by the AP, the PPDU to the pluralityof STAs within an entire frequency bandwidth, wherein the PPDU may betransmitted from each of a plurality of resource unit groups beingallocated to each of the plurality of STAs, wherein each of theplurality of resource unit groups may include a first resource unitgroup and a second resource unit group, wherein the first resource unitgroup may include at least one resource unit, wherein the secondresource unit group may include one tone design resource unit, whereinthe tone design resource unit may include at least one other resourceunit and at least one additional tone unit, and wherein the at least oneadditional tone unit may include leftover tones remaining afterallocating the at least one resource unit and the at least one otherresource unit within the entire frequency band.

In order to achieve the above-described technical object of the presentinvention, according to another aspect of the present invention, anaccess point (AP) allocating resource units using leftover tones in awireless LAN may include a radio frequency (RF) unit transmitting andreceiving radio signals, and a processor being operatively connected tothe RF unit, wherein the processor may be configured to generate a PHYlayer protocol data unit (PPDU) that is to be transmitted to a pluralityof stations (STAs), and to transmit the PPDU to the plurality of STAswithin an entire frequency bandwidth, wherein the PPDU may betransmitted from each of a plurality of resource unit groups beingallocated to each of the plurality of STAs, wherein each of theplurality of resource unit groups may include a first resource unitgroup and a second resource unit group, wherein the first resource unitgroup may include at least one resource unit, wherein the secondresource unit group may include one tone design resource unit, whereinthe tone design resource unit may include at least one other resourceunit and at least one additional tone unit, and wherein the at least oneadditional tone unit may include leftover tones remaining afterallocating the at least one resource unit and the at least one otherresource unit within the entire frequency band.

Effects of the Invention

When allocating a wireless resource for each of a plurality of STAsbased on orthogonal frequency division multiple access (OFDMA), resourceallocation to each of the plurality of STAs may be performed by usingwireless resource units each being defined to have a different size. Byadditionally using leftover tones that remain when allocating wirelessresource units, wireless resource usage (or utilization) efficiency maybe enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

FIG. 2 is a conceptual view illustrating a tone design resource unit forresource allocation according to an exemplary embodiment of the presentinvention.

FIG. 3 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 4 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 5 is a conceptual view illustrating a tone design resource unit forresource allocation according to an exemplary embodiment of the presentinvention.

FIG. 6 is a conceptual view illustrating a tone design resource unit forresource allocation according to an exemplary embodiment of the presentinvention.

FIG. 7 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 8 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 9 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 10 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 11 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 12 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 13 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 14 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 15 is a conceptual view illustrating a DL MU PPDU format accordingto an exemplary embodiment of the present invention.

FIG. 16 is a conceptual view illustrating a transmission of a UL MU PPDUaccording to an exemplary embodiment of the present invention.

FIG. 17 is a block view illustrating a wireless device to which theexemplary embodiment of the present invention can be applied.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

An upper part of FIG. 1 illustrates the structure of an infrastructurebasic service set (BSS) of institute of electrical and electronicengineers (IEEE) 802.11.

Referring the upper part of FIG. 1, the wireless LAN system may includeone or more infrastructure BSSs 100 and 105 (hereinafter, referred to asBSS). The BSSs 100 and 105 as a set of an AP and an STA such as anaccess point (AP) 125 and a station (STA1) 100-1 which are successfullysynchronized to communicate with each other are not concepts indicatinga specific region. The BSS 105 may include one or more STAs 105-1 and105-2 which may be joined to one AP 130.

The BSS may include at least one STA, APs providing a distributionservice, and a distribution system (DS) 110 connecting multiple APs.

The distribution system 110 may implement an extended service set (ESS)140 extended by connecting the multiple BSSs 100 and 105. The ESS 140may be used as a term indicating one network configured by connectingone or more APs 125 or 230 through the distribution system 110. The APincluded in one ESS 140 may have the same service set identification(SSID).

A portal 120 may serve as a bridge which connects the wireless LANnetwork (IEEE 802.11) and another network (e.g., 802.X).

In the BSS illustrated in the upper part of FIG. 1, a network betweenthe APs 125 and 130 and a network between the APs 125 and 130 and theSTAs 100-1, 105-1, and 105-2 may be implemented. However, the network isconfigured even between the STAs without the APs 125 and 130 to performcommunication. A network in which the communication is performed byconfiguring the network even between the STAs without the APs 125 and130 is defined as an Ad-Hoc network or an independent basic service set(IBSS).

A lower part of FIG. 1 illustrates a conceptual view illustrating theIBSS.

Referring to the lower part of FIG. 1, the IBSS is a BSS that operatesin an Ad-Hoc mode. Since the IBSS does not include the access point(AP), a centralized management entity that performs a managementfunction at the center does not exist. That is, in the IBSS, STAs 150-1,150-2, 150-3, 155-4, and 155-5 are managed by a distributed manner. Inthe IBSS, all STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may beconstituted by movable STAs and are not permitted to access the DS toconstitute a self-contained network.

The STA as a predetermined functional medium that includes a mediumaccess control (MAC) that follows a regulation of an Institute ofElectrical and Electronics Engineers (IEEE) 802.11 standard and aphysical layer interface for a radio medium may be used as a meaningincluding all of the APs and the non-AP stations (STAs).

The STA may be called various a name such as a mobile terminal, awireless device, a wireless transmit/receive unit (WTRU), user equipment(UE), a mobile station (MS), a mobile subscriber unit, or just a user.

Hereinafter, in the embodiment of the present invention, data(alternatively, or a frame) which the AP transmits to the STA may beexpressed as a term called downlink data (alternatively, a downlinkframe) and data (alternatively, a frame) which the STA transmits to theAP may be expressed as a term called uplink data (alternatively, anuplink frame). Further, transmission from the AP to the STA may beexpressed as downlink transmission and transmission from the STA to theAP may be expressed as a term called uplink transmission.

In addition, a PHY protocol data unit (PPDU), a frame, and datatransmitted through the downlink transmission may be expressed as termssuch as a downlink PPDU, a downlink frame, and downlink data,respectively. The PPDU may be a data unit including a PPDU header and aphysical layer service data unit (PSDU) (alternatively, a MAC protocoldata unit (MPDU)). The PPDU header may include a PHY header and a PHYpreamble and the PSDU (alternatively, MPDU) may include the frame orindicate the frame (alternatively, an information unit of the MAC layer)or be a data unit indicating the frame. The PHY header may be expressedas a physical layer convergence protocol (PLCP) header as another termand the PHY preamble may be expressed as a PLCP preamble as anotherterm.

Further, a PPDU, a frame, and data transmitted through the uplinktransmission may be expressed as terms such as an uplink PPDU, an uplinkframe, and uplink data, respectively.

In the conventional wireless LAN system, the whole bandwidth may be usedfor downlink transmission to one STA and uplink transmission to one STA.Further, in the wireless LAN system to which the embodiment of thepresent description is applied, the AP may perform downlink (DL)multi-user (MU) transmission based on multiple input multiple output (MUMIMO) and the transmission may be expressed as a term called DL MU MIMOtransmission.

In the wireless LAN system according to the embodiment, an orthogonalfrequency division multiple access (OFDMA) based transmission method issupported for the uplink transmission and/or downlink transmission. Indetail, in the wireless LAN system according to the embodiment, the APmay perform the DL MU transmission based on the OFDMA and thetransmission may be expressed as a term called DL MU OFDMA transmission.When the DL MU OFDMA transmission is performed, the AP may transmit thedownlink data (alternatively, the downlink frame and the downlink PPDU)to the plurality of respective STAs through the plurality of respectivefrequency resources on an overlapped time resource. The plurality offrequency resources may be a plurality of subbands (alternatively, subchannels) or a plurality of resource units (RUs) (alternatively, basictone units or small tone units). The DL MU OFDMA transmission may beused together with the DL MU MIMO transmission. For example, the DL MUMIMO transmission based on a plurality of space-time streams(alternatively, spatial streams) may be performed on a specific subband(alternatively, sub channel) allocated for the DL MU OFDMA transmission.

Further, in the wireless LAN system according to the embodiment, uplinkmulti-user (UL MU) transmission in which the plurality of STAs transmitsdata to the AP on the same time resource may be supported. Uplinktransmission on the overlapped time resource by the plurality ofrespective STAs may be performed on a frequency domain or a spatialdomain.

When the uplink transmission by the plurality of respective STAs isperformed on the frequency domain, different frequency resources may beallocated to the plurality of respective STAs as uplink transmissionresources based on the OFDMA. The different frequency resources may bedifferent subbands (alternatively, sub channels) or different resourcesunits (RUs). The plurality of respective STAs may transmit uplink datato the AP through different frequency resources. The transmission methodthrough the different frequency resources may be expressed as a termcalled a UL MU OFDMA transmission method.

When the uplink transmission by the plurality of respective STAs isperformed on the spatial domain, different time-space streams(alternatively, spatial streams) may be allocated to the plurality ofrespective STAs and the plurality of respective STAs may transmit theuplink data to the AP through the different time-space streams. Thetransmission method through the different spatial streams may beexpressed as a term called a UL MU MIMO transmission method.

The UL MU OFDMA transmission and the UL MU MIMO transmission may be usedtogether with each other. For example, the UL MU MIMO transmission basedon the plurality of space-time streams (alternatively, spatial streams)may be performed on a specific subband (alternatively, sub channel)allocated for the UL MU OFDMA transmission.

In the legacy wireless LAN system which does not support the MU OFDMAtransmission, a multi-channel allocation method is used for allocating awider bandwidth (e.g., a 20 MHz excess bandwidth) to one terminal. Whena channel unit is 20 MHz, multiple channels may include a plurality of20 MHz-channels. In the multi-channel allocation method, a primarychannel rule is used to allocate the wider bandwidth to the terminal.When the primary channel rule is used, there is a limit for allocatingthe wider bandwidth to the terminal. In detail, according to the primarychannel rule, when a secondary channel adjacent to a primary channel isused in an overlapped BSS (OBSS) and is thus busy, the STA may useremaining channels other than the primary channel. Therefore, since theSTA may transmit the frame only to the primary channel, the STA receivesa limit for transmission of the frame through the multiple channels.That is, in the legacy wireless LAN system, the primary channel ruleused for allocating the multiple channels may be a large limit inobtaining a high throughput by operating the wider bandwidth in acurrent wireless LAN environment in which the OBSS is not small.

In order to solve the problem, in the embodiment, a wireless LAN systemis disclosed, which supports the OFDMA technology. That is, the OFDMAtechnique may be applied to at least one of downlink and uplink.Further, the MU-MIMO technique may be additionally applied to at leastone of downlink and uplink. When the OFDMA technique is used, themultiple channels may be simultaneously used by not one terminal butmultiple terminals without the limit by the primary channel rule.Therefore, the wider bandwidth may be operated to improve efficiency ofoperating a wireless resource.

An example of a time-frequency structure, which is assumed in theWirelessLAN system according to this exemplary embodiment may be asdescribed below.

A fast fourier transform (FFT) size/inverse fast fourier transform(IFFT) size may be defined as N-times (wherein N is an integer, e.g.,N=4) of the FFT/IFFT sizes that were used in the legacy WirelessLANsystem. More specifically, as compared to the first part of the HE PPDU,the 4-times size of the FFT/IFFT may be applied to the second part ofthe HE PPDU. For example, 256 FFT/IFFT may be applied for a 20 MHzbandwidth, 512 FFT/IFFT may be applied for a 40 MHz bandwidth, 1024FFT/IFFT may be applied for an 80 MHz bandwidth, and 2048 FFT/IFFT maybe applied to a continuous 160 MHz bandwidth or a non-continuous 160 MHzbandwidth.

Subcarrier space/spacing may correspond to a 1/N-times size (wherein Nis an integer, e.g., when N=4, 78.125 kHz) of the subcarrier spacingthat was used in the legacy WirelessLAN system.

An IDFT/DFT length (or valid symbol length) that is based on inversediscrete fourier transform (IDFT)/discrete fourier transform (DFT) (orFFT/IFFT) may correspond to N-times of the IDFT/DFT length in the legacyWirelessLAN system. For example, in the legacy WirelessLAN system, incase the IDFT/DFT length is equal to 3.2 μs and N=4, in the WirelessLANsystem according to this exemplary embodiment, the IDFT/DFT length maybe equal to 3.2 μs*4(=12.8 μs).

The length of an OFDM symbol may correspond to the IDFT/DFT lengthhaving a length of a guard interval (GI) added thereto. The length ofthe GI may have diverse values, such as 0.4 μs, 0.8 μs, 1.6 μs, 2.4 μs,and 3.2 μs.

An OFDMA structure for a 20 MHz bandwidth may be configured based on26-tone units and 242-tone units. 256 subcarriers may be determinedbased on a 256 inverse fast fourier transform (IFFT) for the 20 MHzbandwidth. And, among the 256 subcarriers, 6 subcarriers may be used asa left guard tone, 3 subcarriers may be used as a DC tone, and 5subcarriers may be used as a right guard tone. A subcarrier may be usedin the same meaning as a tone. Among the 256 subcarriers, the remaining242 tones that remain after excluding the left guard tone, the DC tone,and the right guard tone may be allocated by using OFDMA allocation.26-tone resource units may be allocated within the remaining 242 tones.A maximum of 9 26-tone resource units may be allocated within theremaining 242 tones, and the remaining 8 tones may correspond toleftover tones. A maximum of 9 STAs may be supported for each of themaximum of 9 26-tone resource units. One STA may be allocated with 126-tone resource unit, 2 26-tone resource units, 3 26-tone resourceunits, or 4 26-tone resource units.

An OFDMA structure for a 40 MHz bandwidth may be configured based on26-tone units and 242-tone units. 512 subcarriers may be determinedbased on a 512 IFFT for the 40 MHz bandwidth. And, among the 512subcarriers, 12 subcarriers may be used as a left guard tone, 5subcarriers may be used as a DC tone, and 11 subcarriers may be used asa right guard tone. A subcarrier may be used in the same meaning as atone. Among the 512 subcarriers, the remaining 484 tones that remainafter excluding the left guard tone, the DC tone, and the right guardtone may be allocated by using OFDMA allocation. 26-tone resource unitsand/or 242-tone resource units may be allocated within the remaining 484tones. Based on 242-tone resource units, a maximum of 2 242-toneresource units may be allocated within the 484 tones, and, based on24-tone resource units, a maximum of 26 resource units may be allocatedwithin the 484 tones. In case 1 242-tone resource unit is allocatedwithin the 484 tones, 9 26-tone resource units may be allocated withinthe remaining tones. One STA may be allocated with 1 26-tone resourceunit, 2 26-tone resource units, 3 26-tone resource units, 4 26-toneresource units, or 1 242-tone resource unit.

An OFDMA structure for an 80 MHz bandwidth may be configured based on26-tone units and 242-tone units. 1024 subcarriers may be determinedbased on a 1024 IFFT for the 80 MHz bandwidth. And, among the 1024subcarriers, 12 subcarriers may be used as a left guard tone, 7subcarriers may be used as a DC tone, and 11 subcarriers may be used asa right guard tone. A subcarrier may be used in the same meaning as atone. Among the 1024 subcarriers, the remaining 994 tones that remainafter excluding the left guard tone, the DC tone, and the right guardtone may be allocated by using OFDMA allocation. 26-tone resource unitsand/or 242-tone resource units may be allocated within the remaining 994tones. Based on 242-tone resource units, a maximum of 4 242-toneresource units may be allocated within the 994 tones, and, based on24-tone resource units, a maximum of 37 resource units may be allocatedwithin the 994 tones. In case 2 242-tone resource units are allocatedwithin the 994 tones, 19 26-tone resource units may be allocated withinthe remaining tones. And, in case 3 242-tone resource units areallocated within the 994 tones, 10 26-tone resource units may beallocated within the remaining tones. One STA may be allocated with 126-tone resource unit, 2 26-tone resource units, 3 26-tone resourceunits, 4 26-tone resource units, 1 242-tone resource unit, or 2 242-toneresource units.

Under the assumption presented above, a detailed resource allocationmethod according to an exemplary embodiment of the present inventionwill be disclosed.

FIG. 2 is a conceptual view illustrating a tone design resource unit forresource allocation according to an exemplary embodiment of the presentinvention.

FIG. 2 discloses a tone design method adding additional tones to 26-toneresource unit. According to the exemplary embodiment of the presentinvention, a tone design resource unit may be generated based on a tonedesign, wherein at least one 4-tone additional tone unit correspondingto a multiple of 4 tones is added to a combination of at least one26-tone resource unit. In FIG. 2, the positions of the 26-tone resourceunit configuring the tone design combination and the 4-tone additionaltone unit are merely exemplary, and, therefore, the present inventionwill not be limited only to the example presented herein. Additionally,the resource unit that is expressed as a 26-tone resource unit may alsohave the same meaning as two 13-unit divided resource units.

A resource unit that is generated based on a tone design, wherein oneadditional tone unit (e.g., 4 tones) is added to one resource unithaving a predetermined size corresponding to a specific size (e.g.,26-tone resource unit) may also be expressed by using the term tonedesign resource unit. Unlike the general resource unit, a tone designresource unit may correspond to a non-extendible resource unit. Morespecifically, a 30-tone tone design resource unit, which is configuredby adding a 4-tone additional tone unit to a 26-tone resource unit,cannot be used for the resource allocation of nx30 tones on thefrequency axis. The tone design resource unit may be allocated to an STAin a predetermined (or fixed) position within the frequency axis. Only anumerology corresponding to the number of tones included in the tonedesign resource unit may be used for the tone design resource unit. Forexample, a numerology corresponding to 30 tones may be used for the30-tone tone design resource unit.

According to the exemplary embodiment of the present invention, thenumber of additional tone units being added to the tone design resourceunit may vary in accordance with the number of 26-tone resource unitsconfiguring the tone design resource unit. For example, the number ofadditional tone units that are to be linearly added to the tone designresource unit may be linearly increased in accordance with the number of26-tone resource units configuring the tone design resource unit.

Referring to FIG. 2, the number of 4-tone additional tone units beingadded for the configuration of the tone design resource unit may vary inaccordance with the number of 26-tone resource units configuring thetone design resource unit.

More specifically, in case the number of 26-tone resource unitsconfiguring the tone design resource unit is equal to 1, one (1) 4-toneadditional tone unit may be used so as to define a 30-tone designresource unit 200. 26-tone resource units and/or 242-tone resource unitsmay be allocated within remaining frequency resources that remain afterexcluding the frequency resources that are allocated to the 30-tone tonedesign resource unit 200.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 2, two (2) 4-tone additional tone units may beused so as to define a 60-tone design resource unit (2×26 tones+2×4tones=60 tones) 210. 26-tone resource units and/or 242-tone resourceunits may be allocated within remaining frequency resources that remainafter excluding the frequency resources that are allocated to the60-tone tone design resource unit 210.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 3, three (3) 4-tone additional tone units maybe used so as to define a 90-tone design resource unit (3×26 tones+3×4tones=90 tones) 220. The 90-tone tone design resource unit 220 may bedefined when a leftover tone having a size of 8 tones or more existwithin the 40 MHz bandwidth or 80 MHz bandwidth. 26-tone resource unitsand/or 242-tone resource units may be allocated within remainingfrequency resources that remain after excluding the frequency resourcesthat are allocated to the 90-tone tone design resource unit 220.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 4, four (4) 4-tone additional tone units maybe used so as to define a 120-tone design resource unit (4×26 tones+4×4tones=120 tones) 230. The 120-tone tone design resource unit 230 may bedefined when a leftover tone having a size of 8 tones or more existwithin the 40 MHz bandwidth or 80 MHz bandwidth. 26-tone resource unitsand/or 242-tone resource units may be allocated within remainingfrequency resources that remain after excluding the frequency resourcesthat are allocated to the 120-tone tone design resource unit 230.

FIG. 3 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 3 discloses a case when 2 30-tone design resource units and 726-tone resource units are allocated to a 20 MHz bandwidth.

Referring to FIG. 3, each of the 2 30-tone tone design resource unitsmay be respectively positioned to be adjacent to each of the left guardtone and the right guard tone. 30-tone tone design resource unit 1 310may be configured of a 4-tone additional tone unit and a 26-toneresource unit that are adjacent to the left guard tone. 30-tone tonedesign resource unit 2 320 may be configured of a 4-tone additional toneunit and a 26-tone resource unit that are adjacent to the right guardtone.

Among the 7 26-tone resource units, one 26-tone resource unit that islocated at the center may be divided based on the DC tone, thereby beingdivided into 2 13-tone divided resource units and respectivelyallocated.

In the 20 MHz bandwidth, a left guard tone, 30-tone tone design resourceunit 1 310, 3 26-tone resource units, 1 13-tone divided resource unit, aDC tone, 1 13-tone divided resource unit, 3 26-tone resource units,30-tone tone design resource unit 2 320, and a right guard tone may besequentially allocated.

FIG. 3 discloses a case when a 30-tone design resource unit beingconfigured of a 26-tone resource unit and a 4-tone additional tone unitare used for a 20 MHz bandwidth (or for one 242-tone chunk). The242-tone chunk may have the same meaning as a resource unit included 242tones. The number of tones being used may be equal to 7×26-tone resourceunits+2×30-tone tone design resource units=242 tones, and no leftoverlone may remain. The maximum number of STAs that can be supported withinthe 20 MHz bandwidth may be equal to 9 users. For the 40 MHz bandwidthand the 80 MHz bandwidth, this may be extended and applied by 242-tonechunk units.

By using additional leftover tones as data tones for data transmissionthrough a resource allocation that is based on the above-described tonedesign, wireless resource usage (or utilization) efficiency may beincreased.

FIG. 4 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 4 discloses a method of defining a 30-tone tone design resourceunit by adding additional tones to the 26-tone resource unit. Aplurality of 30-tone resource units may be allocated within thebandwidth. Although the 20 MHz bandwidth is disclosed in FIG. 4 merelyas an example, the 30-tone resource unit may also be used for theresource allocation in the 40 MHz bandwidth and the 80 MHz bandwidth. Incase the 30-tone resource unit is defined, unlike the tone designresource unit, this may correspond to a unit that can be extended (i.e.,a unit that is extendible).

Referring to FIG. 4, 8 30-tone resource units 400 may be allocatedwithin the 20 MHz bandwidth. In this case, among the total 242 tones, 830-tone resource units may be allocated to 240 tones and the remaining 2tones may correspond to leftover tones. In case the resource allocationis performed based on the 30-tone resource unit 400, the 26-toneresource unit may not be allocated within the corresponding bandwidth.In case of using a resource allocation that is based on the 30-toneresource unit 400, resource allocation for a maximum of 8 STAs may beperformed within the 242-tone chunk.

FIG. 5 is a conceptual view illustrating a tone design resource unit forresource allocation according to an exemplary embodiment of the presentinvention.

FIG. 5 discloses a tone design resource unit that is configured of acombination of 26-tone resource units. In FIG. 5, the positions of the26-tone resource unit configuring the tone design combination and the4-tone additional tone unit are merely exemplary, and, therefore, thepresent invention will not be limited only to the example presentedherein. Additionally, the resource unit that is expressed as a 26-toneresource unit may also have the same meaning as two 13-unit dividedresource units.

Basically, a resource unit, which is configured of a combination of atleast one 26-tone resource unit and at least one 4-tone additional toneunit, may be defined as a tone design resource unit and not as a generalresource unit that can be allocated by a multiple based allocation (ormultiplication based allocation). The size corresponding to 26 tones ismerely an exemplary size, and the size corresponding to 4 tones is anexemplary size for an additional tone unit. And, therefore, the tonedesign resource unit may be configured based on a combination ofresource units having diverse sizes and additional tone units havingdiverse sizes. As described above, unlike the general resource unit, atone design resource unit may correspond to a non-extendible resourceunit.

According to the exemplary embodiment of the present invention, thenumber of additional tone unit being added to the tone design resourceunit may be determined independently from the number of 26-unit resourceunits configuring the tone design resource unit. For example, one 4-toneadditional tone unit may be independently added to the tone designresource unit without considering the number of 26-tone resource unitsconfiguring the tone design resource unit.

Referring to FIG. 5, the number of 4-tone additional tone units that areindependently added for the configuration of the tone design resourceunit regardless of the number of 26-tone resource units configuring thetone design resource unit may correspond to a fixed value.

More specifically, in case the number of 26-tone resource unitsconfiguring the tone design resource unit is equal to 1, 1 4-toneadditional tone unit may be used so as to define a 30-tone tone designresource unit 500. The 8 leftover tones within the bandwidth may bedefined as 2 4-tone additional tone units, and each of the two 4-toneadditional tone units may be respectively combined with each of two26-tone resource units, thereby allocating two 30-tone tone designresource units 500 within the 20 MHz bandwidth. 26-tone resource unitsand/or 242-tone resource units may be allocated within the remainingfrequency resources.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 2, 1 4-tone additional tone unit may be usedso as to define a 56-tone tone design resource unit (2×26 tones+1×4tones=56 tones) 510. The 8 leftover tones within the bandwidth may bedefined as 2 4-tone additional tone units (first 4-tone additional toneunit and second 4-tone additional tone unit). A first 4-tone additionaltone unit may configure a first 56-tone tone design resource unit alongwith two 26-tone resource units, and a second 4-tone additional toneunit may configure a second 56-tone tone design resource unit along withanother two 26-tone resource units. 26-tone resource units and/or242-tone resource units may be allocated within the remaining frequencyresources.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 3, 1 4-tone additional tone unit may be usedso as to define an 82-tone tone design resource unit (3×26 tones+1×4tones=82 tones) 520. The 8 leftover tones within the bandwidth may bedefined as 2 4-tone additional tone units (first 4-tone additional toneunit and second 4-tone additional tone unit). A first 4-tone additionaltone unit may configure a first 82-tone tone design resource unit alongwith three 26-tone resource units, and a second 4-tone additional toneunit may configure a second 82-tone tone design resource unit along withanother three 26-tone resource units. 26-tone resource units and/or242-tone resource units may be allocated within the remaining frequencyresources.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 4, 1 4-tone additional tone unit may be usedso as to define a 108-tone tone design resource unit (4×26 tones+1×4tones=108 tones) 530. The 8 leftover tones within the bandwidth may bedefined as 2 4-tone additional tone units (first 4-tone additional toneunit and second 4-tone additional tone unit). A first 4-tone additionaltone unit may configure a first 108-tone tone design resource unit alongwith four 26-tone resource units, and a second 4-tone additional toneunit may configure a second 108-tone tone design resource unit alongwith another four 26-tone resource units. 26-tone resource units and/or242-tone resource units may be allocated within the remaining frequencyresources.

FIG. 6 is a conceptual view illustrating a tone design resource unit forresource allocation according to an exemplary embodiment of the presentinvention.

FIG. 6 discloses a tone design resource unit that is configured by acombination of 4 or more 26-tone resource units. In FIG. 6, thepositions of the 26-tone resource unit configuring the tone designcombination and the 4-tone additional tone unit are merely exemplary,and, therefore, the present invention will not be limited only to theexample presented herein. Additionally, the resource unit that isexpressed as a 26-tone resource unit may also have the same meaning astwo 13-unit divided resource units.

Referring to FIG. 6, in case the number of 26-tone resource unitsconfiguring the tone design resource unit is equal to 4, 2 4-toneadditional tone unit may be used so as to define a 112-tone tone designresource unit (4×26 tones+2×4 tones=112 tones) 600. 26-tone resourceunits and/or 242-tone resource units may be allocated within theremaining frequency resources.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 5, 2 4-tone additional tone unit may be usedso as to define a 138-tone tone design resource unit (5×26 tones+2×4tones=138 tones) 610. 26-tone resource units and/or 242-tone resourceunits may be allocated within the remaining frequency resources.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 6, 2 4-tone additional tone unit may be usedso as to define a 164-tone tone design resource unit (6×26 tones+2×4tones=164 tones) 620. 26-tone resource units and/or 242-tone resourceunits may be allocated within the remaining frequency resources.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 7, 2 4-tone additional tone unit may be usedso as to define a 190-tone tone design resource unit (7×26 tones+2×4tones=190 tones) 630. 26-tone resource units and/or 242-tone resourceunits may be allocated within the remaining frequency resources.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 8, 2 4-tone additional tone unit may be usedso as to define a 216-tone tone design resource unit (8×26 tones+2×4tones=216 tones) (not shown). 26-tone resource units and/or 242-toneresource units may be allocated within the remaining frequencyresources.

In case the number of 26-tone resource units configuring the tone designresource unit is equal to 9, 2 4-tone additional tone unit may be usedso as to define a 242-tone tone design resource unit (9×26 tones+2×4tones=242 tones) (not shown). 26-tone resource units and/or 242-toneresource units may be allocated within the remaining frequencyresources.

An OFDMA based resource allocation may be performed to a 242 chunk. Forexample, a 242 chunk may be configured of a 242-tone resource unit or 926-tone resource units. In case 9 26-tone units are allocated to 234tones within the 242 chunk, a leftover tone having the size of 8 tonesmay remain. The leftover tones corresponding to 8 tones may be combinedwith the resource units, as described above, thereby being used as adata tone and/or pilot tone.

Hereinafter, additional tone design resource units using the leftovertones and a resource allocation method that is based on the tone designresource unit will be disclosed.

FIG. 7 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 7 discloses a resource allocation method that is based on a112-tone tone design resource unit, which is configured of 4 26-toneresource units and 2 4-tone additional tone units (8 leftover tones).

In case the 4-tone additional tone units are allocated to be adjacent to26-tone resource units that are adjacent to the DC tone, the possibleresource allocation method will hereinafter be disclosed.

Referring to FIG. 7, a left guard tone, 4 26-tone resource units, a4-tone first additional tone unit, a 13-tone divided resource unit, a DCtone, a 13-tone divided resource unit, a 4-tone second additional toneunit, 4 26-tone resource units, and a right guard tone may be allocatedwithin the 20 MHz bandwidth.

According to the exemplary embodiment of the present invention, a112-tone tone design resource unit, which is configured of 4 26-toneresource unit and 2 4-tone additional tone units (a 4-tone firstadditional tone unit and a 4-tone second additional tone unit), may bedefined.

The 112-tone tone design resource unit may be allocated to oneallocatable location available for allocating the tone design resourceunit among a plurality of allocatable locations available for allocatingthe tone design resource unit, which are defined based on the 2 4-toneadditional tone units.

For example, a first allocatable location 710 available for allocatingthe tone design resource unit may correspond to the allocation locationsof 3 26-tone resource units, the 4-tone first additional tone unit, 213-tone divided resource units, and the 4-tone second additional toneunit, which are sequentially allocated based on the left guard tone.

A second allocatable location 720 available for allocating the tonedesign resource unit may correspond to the allocation locations of 226-tone resource units, the 4-tone first additional tone unit, 2 13-tonedivided resource units, the 4-tone second additional tone unit, and 126-tone resource unit, which are sequentially allocated based on theleft guard tone.

A third allocatable location 730 available for allocating the tonedesign resource unit may correspond to the allocation locations of 126-tone resource unit, the 4-tone first additional tone unit, 2 13-tonedivided resource units, the 4-tone second additional tone unit, and 226-tone resource units, which are sequentially allocated based on theleft guard tone.

A fourth allocatable location 740 available for allocating the tonedesign resource unit may correspond to the allocation locations of the4-tone first additional tone unit, 2 13-tone divided resource units, the4-tone second additional tone unit, and 3 26-tone resource units, whichare sequentially allocated based on the left guard tone.

In case the 112-tone tone design resource unit corresponds to oneallocatable location available for the resource allocation of the tonedesign resource unit, among the plurality of allocatable locationsavailable for the resource allocation of the tone design resource unit,a subband selective transmission may be performed. More specifically,the tone design resource unit may be allocated to one allocatablelocation available for the resource allocation of the tone designresource unit, among the plurality of allocatable locations availablefor the resource allocation of the tone design resource unit, inaccordance with the channel status.

Table 1 shown below discloses the allocation of resource units inaccordance with the number of STAs that are allocated with resourceunits within the frequency axis.

TABLE 1 Allocation K 4x26 + 8 case (17 set) 1x26 2x26 3x26  

  1 3 0 0 3 0 2 3 0 1 1 1  

   

   

   

   

   

  4 4 0 3 1 0 5 4 1 1 2 0 6 4 1 2 0 1 7 4 2 0 1 1 8 5 1 4 0 0 9 5 2 2 10 10 5 3 0 2 0 11 5 3 1 0 1 12 6 3 3 0 0 13 6 4 1 1 0 14 6 5 0 0 1 15 75 2 0 0 16 7 6 0 1 0 17 8 7 1 0 0 18 9 9 0 0 0

In Table 1, a case when 9 26-tone resource units are allocated withinthe 20 MHz bandwidth will be assumed.

Referring to Table 1, one STA may be allocated with a first resourceunit group including 1 26-tone resource unit, a second resource unitgroup including 2 26-tone resource units, a third resource unit groupincluding 3 26-tone resource units, or a fourth resource unit groupincluding a 112-tone tone design resource unit, which is configured of 426-tone resource units and 2 4-tone additional tone units (8 leftovertones).

For example, a first allocation case corresponds to a case when each of3 STAs is respectively allocated with each of 3 third resource unitgroups. More specifically, STA1 may be allocated with 3 26-tone resourceunits, STA2 may be allocated with 3 26-tone resource units, and STA3 maybe allocated with 3 26-tone resource units.

A third allocation case shows an exemplary case when resource allocationis not possible. Since only one 112-tone tone design resource unit canbe allocated within the frequency axis, the resource allocation shown inthe third allocation case cannot be performed. Also, resource allocationthat is based only on at least one specific resource unit group may notbe possible (or may not be performed) in a specific allocation case.

The definition of the allocation of a new interleaver/new pilot for the112-tone tone design resource unit may be required. The 112-tone tonedesign resource unit may be usefully used in a 10 MHz bandwidth.

According to the exemplary embodiment of the present invention, thelocation of the 4-tone additional tone unit may change (or vary).

According to another exemplary embodiment of the present invention, withthe change (or variation) in the location of the 4-tone additional toneunit, resource allocation that is based on a left guard tone, [26, 26,26, 4, 26, 26, 26, 4, 26, 26, 26], and a right guard tone may beperformed. In this case, the 112-tone tone design resource unit may beallocated to the locations of the resource allocation units inparentheses (or brackets), such as [26, 26, (26, 4, 26, 26, 26, 4), 26,26, 26] and [26, 26, 26, (4, 26, 26, 26, 4), 26, 26, 26], and the 4-toneadditional tone unit.

FIG. 8 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 8 discloses a resource allocation method that is based on a 56-tonetone design resource unit, which is configured of 2 26-tone resourceunits and 1 4-tone additional tone unit (4 leftover tones).

Referring to FIG. 8, a left guard tone, 2 26-tone resource units, a4-tone first additional tone unit, 2 26-tone resource units, a 13-tonedivided resource unit, a DC tone, a 13-tone divided resource unit, 226-tone resource units, a 4-tone second additional tone unit, 2 26-toneresource units, and a right guard tone may be allocated within the 20MHz bandwidth.

According to the exemplary embodiment of the present invention, a56-tone tone design resource unit, which is configured of 2 26-toneresource units and 1 4-tone additional tone unit, may be defined.

The 1 12-tone tone design resource unit may be allocated to oneallocatable location available for allocating the tone design resourceunit among a plurality of allocatable locations available for allocatingthe tone design resource unit, which are defined based on the 4-tonefirst additional tone unit or the 4-tone second additional tone unit.

For example, a first allocatable location 800 available for allocatingthe tone design resource unit may correspond to the allocation locationsof 2 26-tone resource units and the 4-tone first additional tone unit,which are sequentially allocated based on the left guard tone.

A second allocatable location 810 available for allocating the tonedesign resource unit may correspond to the allocation locations of 126-tone resource unit, the 4-tone first additional tone unit, and 126-tone resource unit, which are sequentially allocated based on theleft guard tone.

A third allocatable location 820 available for allocating the tonedesign resource unit may correspond to the allocation locations of the4-tone first additional tone unit and 2 26-tone resource units, whichare sequentially allocated based on the left guard tone.

A fourth allocatable location 830 available for allocating the tonedesign resource unit may correspond to the allocation locations of 226-tone resource units and the 4-tone second additional tone unit, whichare sequentially allocated based on the left guard tone.

A fifth allocatable location 840 available for allocating the tonedesign resource unit may correspond to the allocation locations of 126-tone resource unit, the 4-tone second additional tone unit, and 126-tone resource unit, which are sequentially allocated based on theleft guard tone.

A sixth allocatable location 850 available for allocating the tonedesign resource unit may correspond to the allocation locations of the4-tone second additional tone unit and 2 26-tone resource units, whichare sequentially allocated based on the left guard tone.

Similarly, in case the 56-tone tone design resource unit corresponds toone allocatable location available for the resource allocation of thetone design resource unit, among the plurality of allocatable locationsavailable for the resource allocation of the tone design resource unit,a subband selective transmission may be performed. More specifically,the tone design resource unit may be allocated to one allocatablelocation available for the resource allocation of the tone designresource unit, among the plurality of allocatable locations availablefor the resource allocation of the tone design resource unit, inaccordance with the channel status.

Table 2 shown below discloses the allocation of resource units inaccordance with the number of STAs that are allocated with resourceunits within the frequency axis.

TABLE 2 Allocation K 2x26 + 4 Case (15 set) 1x26  

  3x26 4x26 1 3 0 0 3 0 2 3 0 1 1 1 3 3 1 0 0 2 4 4  

   

   

  0 5 4 1 1 2 0 6 4 1 2 0 1 7 4 2 0 1 1  

   

   

  4  

   

  9 5 2 2 1 0 10 5 3 0 2 0 11 5 3 1 0 1  

   

   

   

   

   

  13 6 4 1 1 0 14 6 5 0 0 1 15 7 5 2 0 0 16 7 6 0 1 0 17 8 7 1 0 0 18 99 0 0 0

In Table 2, a case when 9 26-tone resource units are allocated withinthe 20 MHz bandwidth will be assumed.

Referring to Table 2, one STA may be allocated with a first resourceunit group including 1 26-tone resource unit, a second resource unitgroup including a tone design resource unit, which is configured of 226-tone resource units and 1 4-tone additional tone unit, a thirdresource unit group including 3 26-tone resource units, or a fourthresource unit group including 4 26-tone resource units.

For example, a second allocation case corresponds to a case when each of3 STAs is respectively allocated with the second resource unit group,the third resource unit group, and the fourth resource unit group. Morespecifically, STA1 may be allocated with the second resource unit group,STA2 may be allocated with the third resource unit group, and STA3 maybe allocated with the fourth resource unit group.

A fourth allocation case/eighth allocation case/twelfth allocation caserespectively show exemplary cases when resource allocation is notpossible. Since the total number of leftover tones within the 20 MHzbandwidth is equal to 8 tones, and since up to 2 second resource unitgroups can be allocated, the fourth allocation case/eighth allocationcase/twelfth allocation case may correspond to cases, wherein resourceallocation is not possible.

Interleaving is performed on the 56-tone tone design resource unit basedon the conventional 52-size interleaver, and 4 tones may be allocated asthe pilot tone. The 56-tone tone design resource unit may be usefullyused in a 5 MHz bandwidth.

According to the exemplary embodiment of the present invention, thelocation of the 4-tone additional tone unit may change (or vary).

According to another exemplary embodiment of the present invention, withthe change (or variation) in the location of the 4-tone additional toneunit, resource allocation that is based on a left guard tone, [26, 26,26, 4, 26, 26, 26, 4, 26, 26, 26], and a right guard tone may beperformed. In this case, the 56-tone tone design resource unit may beallocated to the locations of the resource allocation units inparentheses (or brackets), such as [26, (26, 26, 4), 26, 26, 26, 4, 26,26, 26] and [26, 26, (26, 4, 26), 26, 26, 4, 26, 26, 26], [26, 26, 26,4, 26, 26, (26, 4, 26), 26, 26] and [26, 26, 26, 4, 26, 26, 26, (4, 26,26), 26], and the 4-tone additional tone unit.

According to yet another exemplary embodiment of the present invention,with the change (or variation) in the location of the 4-tone additionaltone unit, resource allocation that is based on a left guard tone, [26,26, 26, 26, 4, 26, 4, 26, 26, 26, 26], and a right guard tone may beperformed. In this case, the 56-tone tone design resource unit may beallocated to the locations of the resource allocation units inparentheses (or brackets), such as [26, 26, (26, 26, 4), 26, 4, 26, 26,26, 26] and [26, 26, 26, 26, 4, 26, (4, 26, 26), 26, 26], and the 4-toneadditional tone unit.

FIG. 9 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 9 discloses a resource allocation method that is based on an82-tone tone design resource unit, which is configured of 3 26-toneresource units and 1 4-tone additional tone unit (4 leftover tones).

Referring to FIG. 9, a left guard tone, 3 26-tone resource units, a4-tone first additional tone unit, 1 26-tone resource unit, a 13-tonedivided resource unit, a DC tone, a 13-tone divided resource unit, 126-tone resource unit, a 4-tone second additional tone unit, 3 26-toneresource units, and a right guard tone may be allocated within the 20MHz bandwidth.

According to the exemplary embodiment of the present invention, an82-tone tone design resource unit, which is configured of 3 26-toneresource unit and 1 4-tone additional tone unit, may be defined.

The 82-tone tone design resource unit may be allocated to oneallocatable location available for allocating the tone design resourceunit among a plurality of allocatable locations available for allocatingthe tone design resource unit, which are defined based on the 4-tonefirst additional tone unit or the 4-tone second additional tone unit.

For example, a first allocatable location 900 available for allocatingthe tone design resource unit may correspond to the allocation locationsof 3 26-tone resource units and the 4-tone first additional tone unit,which are sequentially allocated based on the left guard tone.

A second allocatable location 910 available for allocating the tonedesign resource unit may correspond to the allocation locations of 226-tone resource units, the 4-tone first additional tone unit, and 126-tone resource unit, which are sequentially allocated based on theleft guard tone.

A third allocatable location 920 available for allocating the tonedesign resource unit may correspond to the allocation locations of 126-tone resource unit, the 4-tone second additional tone unit, and 226-tone resource units, which are sequentially allocated based on theleft guard tone.

A fourth allocatable location 930 available for allocating the tonedesign resource unit may correspond to the allocation locations of the4-tone second additional tone unit, and 3 26-tone resource units, whichare sequentially allocated based on the left guard tone.

Similarly, in case the 82-tone tone design resource unit corresponds toone allocatable location available for the resource allocation of thetone design resource unit, among the plurality of allocatable locationsavailable for the resource allocation of the tone design resource unit,a subband selective transmission may be performed. More specifically,the tone design resource unit may be allocated to one allocatablelocation available for the resource allocation of the tone designresource unit, among the plurality of allocatable locations availablefor the resource allocation of the tone design resource unit, inaccordance with the channel status.

Table 3 shown below discloses the allocation of resource units inaccordance with the number of STAs that are allocated with resourceunits within the frequency axis.

TABLE 3 Allocation K 3x26 + 4 case (17 set) 1x26 2x26  

  4x26  

   

   

   

   

   

  2 3 0 1 1 1 3 3 1 0 0 2 4 4 0 3 1 0 5 4 1 1 2 0 6 4 1 2 0 1 7 4 2 0 11 8 5 1 4 0 0 9 5 2 2 1 0 10 5 3 0 2 0 11 5 3 1 0 1 12 6 3 3 0 0 13 6 41 1 0 14 6 5 0 0 1 15 7 5 2 0 0 16 7 6 0 1 0 17 8 7 1 0 0 18 9 9 0 0 0

In Table 3, a case when 9 26-tone resource units are allocated withinthe 20 MHz bandwidth will be assumed.

Referring to Table 3, one STA may be allocated with a first resourceunit group including 1 26-tone resource unit, a second resource unitgroup including 2 26-tone resource units, a third resource unit groupincluding 3 26-tone resource units and 1 4-tone additional tone unit,and a fourth resource unit group including 4 26-tone resource units.

For example, a fourth allocation case corresponds to a case when each of4 STAs is respectively allocated with 3 second resource unit groups, andthe third resource unit group. More specifically, STA1 may be allocatedwith the second resource unit group, STA2 may be allocated with thesecond resource unit group, STA3 may be allocated with the thirdresource unit group, and STA4 may be allocated with the third resourceunit group.

A first allocation case shows an exemplary case when resource allocationis not possible. Since the total number of leftover tones within the 20MHz bandwidth is equal to 8 tones, and since up to 2 second resourceunit groups can be allocated, the first allocation case may correspondto a case, wherein resource allocation is not possible.

The definition of the allocation of a new interleaver/new pilot for the82-tone tone design resource unit may be required.

According to the exemplary embodiment of the present invention, thelocation of the 4-tone additional tone unit may change (or vary).

For example, according to another exemplary embodiment of the presentinvention, with the change (or variation) in the location of the 4-toneadditional tone unit, resource allocation that is based on a left guardtone, [26, 26, 26, 26, 4, 26, 4, 26, 26, 26, 26], and a right guard tonemay be performed. In this case, the 82-tone tone design resource unitmay be allocated to the locations of the resource allocation units inparentheses (or brackets), such as [26, (26, 26, 26, 4), 26, 4, 26, 26,26, 26] and [26, 26, 26, 26, 4, 26, (4, 26, 26, 26), 26], and the 4-toneadditional tone unit.

According to yet another exemplary embodiment of the present invention,with the change (or variation) in the location of the 4-tone additionaltone unit, resource allocation that is based on a left guard tone, [26,26, 4, 26, 26, 26, 26, 26, 4, 26, 26], and a right guard tone may beperformed. In this case, the 82-tone tone design resource unit may beallocated to the locations of the resource allocation units inparentheses (or brackets), such as [26, (26, 4, 26, 26), 26, 26, 26, 4,26, 26] and [26, 26, 4, 26, 26, 26, (26, 26, 4, 26), 26], and so on, andthe 4-tone additional tone unit.

According to yet another exemplary embodiment of the present invention,with the change (or variation) in the location of the 4-tone additionaltone unit, resource allocation that is based on a left guard tone, [26,4, 26, 26, 26, 26, 26, 26, 26, 4, 26], and a right guard tone may beperformed. In this case, the 82-tone tone design resource unit may beallocated to the locations of the resource allocation units inparentheses (or brackets), such as [26, (4, 26, 26, 26), 26, 26, 26, 26,4, 26] and [26, 4, 26, 26, 26, 26, (26, 26, 26, 4), 26], and so on, andthe 4-tone additional tone unit.

FIG. 10 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 10 discloses a resource allocation method that is based on a28-tone tone design resource unit, which is configured of 1 26-toneresource unit and 1 2-tone additional tone unit (2 leftover tones).

Referring to FIG. 10, a left guard tone, 1 26-tone resource unit, a2-tone first additional tone unit, 2 26-tone resource units, a 2-tonesecond additional tone unit, 1 26-tone resource unit, a 13-tone dividedresource unit, a DC tone, a 13-tone divided resource unit, 1 26-toneresource unit, a 2-tone third additional tone unit, 2 26-tone resourceunits, a 2-tone fourth additional tone unit, 1 26-tone resource unit,and a right guard tone may be allocated within the 20 MHz bandwidth.

According to the exemplary embodiment of the present invention, a28-tone tone design resource unit, which is configured of 1 26-toneresource unit and 1 2-tone additional tone unit, may be defined.

The 28-tone tone design resource unit may be allocated to oneallocatable location available for allocating the tone design resourceunit among a plurality of allocatable locations available for allocatingthe tone design resource unit, which are defined based on the 2-tonefirst additional tone unit to the 2-tone fourth additional tone unit.

For example, a first allocatable location 1000 available for allocatingthe tone design resource unit may correspond to the allocation locationsof 1 26-tone resource unit and the 2-tone first additional tone unit,which are sequentially allocated based on the left guard tone.

A second allocatable location 1010 available for allocating the tonedesign resource unit may correspond to the allocation locations of the2-tone first additional tone unit and 1 26-tone resource unit, which aresequentially allocated based on the left guard tone.

A third allocatable location 1020 available for allocating the tonedesign resource unit may correspond to the allocation locations of 126-tone resource unit and the 2-tone second additional tone unit, whichare sequentially allocated based on the left guard tone.

A fourth allocatable location 1030 available for allocating the tonedesign resource unit may correspond to the allocation locations of the2-tone second additional tone unit and 1 26-tone resource unit, whichare sequentially allocated based on the left guard tone.

A fifth allocatable location 1040 available for allocating the tonedesign resource unit may correspond to the allocation locations of 126-tone resource unit and the 2-tone third additional tone unit, whichare sequentially allocated based on the left guard tone.

A sixth allocatable location 1050 available for allocating the tonedesign resource unit may correspond to the allocation locations of the2-tone third additional tone unit and 1 26-tone resource unit, which aresequentially allocated based on the left guard tone.

A seventh allocatable location 1060 available for allocating the tonedesign resource unit may correspond to the allocation locations of 126-tone resource unit and the 2-tone fourth additional tone unit, whichare sequentially allocated based on the left guard tone.

An eighth allocatable location 1070 available for allocating the tonedesign resource unit may correspond to the allocation locations of the2-tone fourth additional tone unit and 1 26-tone resource unit, whichare sequentially allocated based on the left guard tone.

Similarly, in case the 28-tone tone design resource unit corresponds toone allocatable location available for the resource allocation of thetone design resource unit, among the plurality of allocatable locationsavailable for the resource allocation of the tone design resource unit,a subband selective transmission may be performed. More specifically,the tone design resource unit may be allocated to one allocatablelocation available for the resource allocation of the tone designresource unit, among the plurality of allocatable locations availablefor the resource allocation of the tone design resource unit, inaccordance with the channel status.

Table 4 shown below discloses the allocation of resource units inaccordance with the number of STAs that are allocated with resourceunits within the frequency axis.

TABLE 4 Allocation K 1x26 + 2 case (13 set)  

  2x26 3x26 4x26 1 3 0 0 3 0 2 3 0 1 1 1 3 3 1 0 0 2 4 4 0 3 1 0 5 4 1 12 0 6 4 1 2 0 1 7 4 2 0 1 1 8 5 1 4 0 0 9 5 2 2 1 0 10 5 3 0 2 0 11 5 31 0 1 12 6 3 3 0 0 13 6 4 1 1 0  

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

   

 

In Table 4, a case when 9 26-tone resource units are allocated withinthe 20 MHz bandwidth will be assumed.

Referring to Table 4, one STA may be allocated with a first resourceunit group including a tone design resource unit, which is configured of1 26-tone resource unit and 1 2-tone additional tone unit, a secondresource unit group including 2 26-tone resource units, a third resourceunit group including 3 26-tone resource units, and a fourth resourceunit group including 4 26-tone resource units.

For example, a fifth allocation case corresponds to a case when each of4 STAs is respectively allocated with one first resource unit group, onesecond resource unit group, and 2 third resource unit groups. Morespecifically, STA1 may be allocated with the first resource unit group,STA2 may be allocated with the second resource unit group, STA3 may beallocated with the third resource unit group, and STA4 may be allocatedwith the third resource unit group.

A fourteenth allocation case shows an exemplary case when resourceallocation is not possible. Since the total number of leftover toneswithin the 20 MHz bandwidth is equal to 8 tones, and since up to 4 firstresource unit groups can be allocated, the fourteenth allocation casemay correspond to a case, wherein resource allocation is not possible.

FIG. 11 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 11 discloses a resource allocation method that is based on a112-tone first tone design resource unit, which is configured of 426-tone resource unit and 2 4-tone additional tone units (8 leftovertones), and a 56-tone second tone design resource unit, which isconfigured of 2 26-tone resource units and 1 4-tone additional tone unit(4 leftover tones).

Referring to FIG. 11, a left guard tone, 4 26-tone resource units, a4-tone first additional tone unit, a 13-tone divided resource unit, a DCtone, a 13-tone divided resource unit, a 4-tone second additional toneunit, 4 26-tone resource units, and a right guard tone may be allocatedwithin the 20 MHz bandwidth.

According to the exemplary embodiment of the present invention, a112-tone first tone design resource unit 1100, which is configured of 426-tone resource units and 2 4-tone additional tone units, and a 56-tonesecond tone design resource unit 1150, which is configured of 2 26-toneresource units and 1 4-tone additional tone unit, may be defined.

Just as described above, a plurality of allocatable locations availablefor the resource allocation of each of the first tone design resourceunit 1100 and the second tone design resource unit 1150 may beconfigured, and each of the first tone design resource unit 1100 and thesecond tone design resource unit 1150 may be respectively allocated toone allocatable location available for the resource allocation of thetone design resource unit among a plurality of allocatable locationsavailable for the resource allocation of the tone design resource unit.

Table 5 shown below discloses the allocation of resource units inaccordance with the number of STAs that are allocated with resourceunits within the frequency axis.

TABLE 5 Allocation K 2x26 + 4 4x26 + 8 case ( 11 set) 1x26  

  3x26  

  1 3 0 0 3 0  

   

   

   

   

   

   

   

   

   

   

   

  4 4  

   

   

   

  5 4 1 1 2 0  

  4  

   

   

   

  7 4 2 0 1 1  

   

   

  4  

   

  9 5 2 2 1 0 10 5 3 0 2 0  

   

   

   

   

   

   

   

   

   

   

   

  13 6 4 1 1 0 14 6 5 0 0 1 15 7 5 2 0 0 16 7 6 0 1 0 17 8 7 1 0 0 18 99 0 0 0

In Table 5, a case when 9 26-tone resource units are allocated withinthe 20 MHz bandwidth will be assumed.

Referring to Table 5, one STA may be allocated with a first resourceunit group including 1 26-tone resource unit, a second resource unitgroup including a first tone design resource unit 1100, which isconfigured of 2 26-tone resource units and 1 4-tone additional toneunit, a third resource unit group including 3 26-tone resource units,and a fourth resource unit group including a second tone design resourceunit 1150, which is configured of 4 26-tone resource units and 2 4-toneadditional tone units.

In case the first tone design resource unit 1100 and the second tonedesign resource unit 1150 are being supported, 11 different types ofallocation cases may be supported for the 20 MHz bandwidth.

FIG. 12 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 12 discloses a resource allocation method that is based on a56-tone first tone design resource unit, which is configured of 226-tone resource units and 1 4-tone additional tone unit (4 leftovertones), and an 82-tone second tone design resource unit, which isconfigured of 3 26-tone resource units and 1 4-tone additional tone unit(4 leftover tones).

Referring to FIG. 12, a left guard tone, 2 26-tone resource units, a4-tone first additional tone unit, 2 26-tone resource units, a 13-tonedivided resource unit, a DC tone, a 13-tone divided resource unit, 226-tone resource units, a 4-tone second additional tone unit, 2 26-toneresource units, and a right guard tone may be allocated within the 20MHz bandwidth.

According to the exemplary embodiment of the present invention, a56-tone first tone design resource unit 1200, which is configured of 226-tone resource units and 1 4-tone additional tone unit, and an 82-tonesecond tone design resource unit 1250, which is configured of 3 26-toneresource units and 1 4-tone additional tone unit, may be defined.

Just as described above, a plurality of allocatable locations availablefor the resource allocation of each of the first tone design resourceunit 1200 and the second tone design resource unit 1250 may beconfigured, and each of the first tone design resource unit 1200 and thesecond tone design resource unit 1250 may be respectively allocated toone allocatable location available for the resource allocation of thetone design resource unit among a plurality of allocatable locationsavailable for the resource allocation of the tone design resource unit.

Table 6 shown below discloses the allocation of resource units inaccordance with the number of STAs that are allocated with resourceunits within the frequency axis.

TABLE 6 Allocation K 2x26 + 4 3x26 + 4 case (12 set) 1x26  

   

  4x26  

   

   

   

   

   

  2 3 0 1 1 1 3 3 1 0 0 2 4 4  

   

   

   

   

  4  

   

   

   

  6 4 1 2 0 1 7 4 2 0 1 1  

   

   

  4  

   

   

   

   

   

   

   

  10 5 3 0 2 0 11 5 3 1 0 1  

   

   

   

   

   

  13 6 4 1 1 0 14 6 5 0 0 1 15 7 5 2 0 0 16 7 6 0 1 0 17 8 7 1 0 0 18 99 0 0 0

In Table 6, a case when 9 26-tone resource units are allocated withinthe 20 MHz bandwidth will be assumed.

Referring to Table 6, one STA may be allocated with a first resourceunit group including 1 26-tone resource unit, a second resource unitgroup including a first tone design resource unit 1200, which isconfigured of 2 26-tone resource units and 1 4-tone additional toneunit, a third resource unit group including a second tone designresource unit 1250, which is configured of 3 26-tone resource units and1 4-tone additional tone unit, and a fourth resource unit groupincluding 4 26-tone resource units.

In case the first tone design resource unit 1200 and the second tonedesign resource unit 1250 are being supported, 12 different types ofallocation cases may be supported for the 20 MHz bandwidth.

Although gain of the subband selective transmission of the second tonedesign resource unit 1250 may be deduced due to the allocation of thefirst tone design resource unit 1200, the allocation of the first tonedesign resource unit 1200 and the second tone design resource unit 1250may be determined through the scheduling of the AP.

FIG. 13 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 13 discloses a resource allocation method that is based on a112-tone first tone design resource unit, which is configured of 426-tone resource unit and 2 4-tone additional tone units (8 leftovertones), and a 56-tone second tone design resource unit, which isconfigured of 2 26-tone resource units and 1 4-tone additional tone unit(4 leftover tones).

Referring to FIG. 13, a left guard tone, 2 26-tone resource units, a4-tone first additional tone unit, 2 26-tone resource units, a 13-tonedivided resource unit, a DC tone, a 13-tone divided resource unit, 226-tone resource units, a 4-tone second additional tone unit, 2 26-toneresource units, and a right guard tone may be allocated within the 20MHz bandwidth.

According to the exemplary embodiment of the present invention, a112-tone first tone design resource unit, which is configured of 426-tone resource units and 2 4-tone additional tone units, and a 56-tonesecond tone design resource unit, which is configured of 2 26-toneresource units and 1 4-tone additional tone unit, may be defined.

Just as described above, a plurality of allocatable locations availablefor the resource allocation of each of the first tone design resourceunit and the second tone design resource unit may be configured, andeach of the first tone design resource unit and the second tone designresource unit may be respectively allocated to one allocatable locationavailable for the resource allocation of the tone design resource unitamong a plurality of allocatable locations available for the resourceallocation of the tone design resource unit. In case of the first tonedesign resource unit, the first tone design resource unit may beallocated not only to contiguous frequency resources but also tonon-contiguous frequency resources.

For example, in case the resource allocation structure for the 20 MHzbandwidth corresponds to [26, 26, 4, 26, 26, 26, 26, 26, 4, 26, 26], thefirst allocatable location 1310 of the first tone design resource unitmay correspond to the allocation locations of the resource units inparentheses (or brackets), such as [(26, 26, 4), 26, 26, 26, 26, 26, (4,26, 26)]. The second allocatable location 1320 of the first tone designresource unit may correspond to the allocation locations of the resourceunits in parentheses (or brackets), such as [26, (26, 4, 26), 26, 26,26, (26, 4, 26), 26]. The third allocatable location 1330 of the firsttone design resource unit may correspond to the allocation locations ofthe resource units in parentheses (or brackets), such as [26, 26, (4,26, 26), 26, (26, 26, 4), 26, 26].

Table 7 shown below discloses the allocation of resource units inaccordance with the number of STAs that are allocated with resourceunits within the frequency axis.

TABLE 7 Allocation K 2x26 + 4 4x26 + 8 case (11 set) 1x26  

  3x26  

  1 3 0 0 3 0 2 3 0 1 1 1 3 3 1 0 0 2 4 4 0 3 1 0 5 4 1 1 2 0 6 4 1 2 01 7 4 2 0 1 1 8 5 1 4 0 0 9 5 2 2 1 0 10 5 3 0 2 0 11 5 3 1 0 1 12 6 3 30 0 13 6 4 1 1 0 14 6 5 0 0 1 15 7 5 2 0 0 16 7 6 0 1 0 17 8 7 1 0 0 189 9 0 0 0

In Table 7, a case when 9 26-tone resource units are allocated withinthe 20 MHz bandwidth will be assumed.

Referring to Table 7, one STA may be allocated with a first resourceunit group including 1 26-tone resource unit, a second resource unitgroup including a first tone design resource unit, which is configuredof 2 26-tone resource units and 1 4-tone additional tone unit, a thirdresource unit group including 3 26-tone resource units, and a fourthresource unit group including a second tone design resource unit, whichis configured of 4 26-tone resource units and 2 4-tone additional toneunits.

In case the first tone design resource unit and the second tone designresource unit are being supported, 11 different types of allocationcases may be supported for the 20 MHz bandwidth.

FIG. 14 is a conceptual view illustrating a resource allocation methodaccording to an exemplary embodiment of the present invention.

FIG. 14 discloses a resource allocation method that is based on a112-tone first tone design resource unit, which is configured of 426-tone resource unit and 2 4-tone additional tone units (8 leftovertones), and a 56-tone second tone design resource unit, which isconfigured of 2 26-tone resource units and 1 4-tone additional tone unit(4 leftover tones). Most particularly, FIG. 14 discloses a method forperforming scheduling of resource units by additionally using a resourceunit group including 2 26-tone resource units.

Referring to FIG. 14, a left guard tone, 2 26-tone resource units, a4-tone first additional tone unit, 2 26-tone resource units, a 13-tonedivided resource unit, a DC tone, a 13-tone divided resource unit, 226-tone resource units, a 4-tone second additional tone unit, 2 26-toneresource units, and a right guard tone may be allocated within the 20MHz bandwidth.

According to the exemplary embodiment of the present invention, a112-tone first tone design resource unit, which is configured of 426-tone resource units and 2 4-tone additional tone units, and a 56-tonesecond tone design resource unit, which is configured of 2 26-toneresource units and 1 4-tone additional tone unit, may be defined.

As described above in FIG. 13, a plurality of allocatable locationsavailable for the resource allocation of each of the first tone designresource unit and the second tone design resource unit may beconfigured, and each of the first tone design resource unit and thesecond tone design resource unit may be respectively allocated to oneallocatable location available for the resource allocation of the tonedesign resource unit among a plurality of allocatable locationsavailable for the resource allocation of the tone design resource unit.In case of the first tone design resource unit, the first tone designresource unit may be allocated not only to contiguous frequencyresources but also to non-contiguous frequency resources.

According to the exemplary embodiment of the present invention,allocation of resource units may be scheduled by additionally defining aseparate resource unit group including 2 26-tone resource units insteadof the first tone design resource unit.

Table 8 shown below discloses the allocation of resource units inaccordance with the number of STAs that are allocated with resourceunits within the frequency axis.

TABLE 8 Allocation K 2x26 + 4 4x26 + 8 case (17 set) 1x26 w 2x26 3x26  

  1 3 0 0 3 0 2 3 0 1¹⁾ 1 1 3  

   

   

   

   

  4 4 0 3¹⁾ 1 0 5 4 1 1²⁾ 2 0 6 4 1 2¹⁾ 0 1 7 4 2 0 1 1 8 5 1 4¹⁾ 0 0 95 2 2²⁾ 1 0 10 5 3 0 2 0 11 5 3 1¹⁾ 0 1 12 6 3 3¹⁾ 0 0 13 6 4 1²⁾ 1 0 146 5 0 0 1 15 7 5 2²⁾ 0 0 16 7 6 0 1 0 17 8 7 1²⁾ 0 0 18 9 9 0 0 0 Thesecond resource unit group 1400 and the (2-1)^(th) resource unit group1410 may be used to replace one another. ¹⁾may indicate the usage of the(2-1)^(th) resource unit group 1410, and ²⁾may indicate the usage of thesecond resource unit group 1400.

In Table 8, a case when 9 26-tone resource units are allocated withinthe 20 MHz bandwidth will be assumed.

Referring to Table 8, one STA may be allocated with a first resourceunit group including 1 26-tone resource unit, a second resource unitgroup 1400 including a first tone design resource unit, which isconfigured of 2 26-tone resource units and 1 4-tone additional toneunit, a (2-1)^(th) resource unit group 1410 including 2 26-tone resourceunits, a third resource unit group including 3 26-tone resource units,and a fourth resource unit group including a second tone design resourceunit, which is configured of 4 26-tone resource units and 2 4-toneadditional tone units.

In this case, in case the first tone design resource unit and the secondtone design resource unit are being supported, 17 different types ofallocation cases may be supported for the 20 MHz bandwidth.

FIG. 15 is a conceptual view illustrating a DL MU PPDU format accordingto an exemplary embodiment of the present invention.

FIG. 15 discloses a DL U PPDU format that is transmitted by the AP basedon OFDMA according to the exemplary embodiment of the present invention.

Referring to FIG. 15, a PPDU header of a DL MU PPDU may include alegacy-short training field (L-STF), a legacy-long training field(L-LTF), a legacy-signal (L-SIG), a high efficiency-signal A (HE-SIG A),a high efficiency-signal B (HE-SIG B), a high efficiency-short trainingfield (HE-STF), a high efficiency-long training field (HE-LTF), and adata field (or MAC payload). The PPDU may be divided into a legacy part,which consists of a part starting from the PHY header to the L-SIG, anda high efficiency (HE) part, which consists of a part after the L-SIG.

The L-STF 1500 may include a short training orthogonal frequencydivision multiplexing (OFDM) symbol. The L-STF 1500 may be used forframe detection, automatic gain control (AGC), diversity detection, andcoarse frequency/time synchronization.

The L-LTF 1510 may include a long training orthogonal frequency divisionmultiplexing (OFDM) symbol. The L-LTF 1510 may be used for finefrequency/time synchronization and channel prediction.

The L-SIG 1520 may be used for transmitting control information. TheL-SIG 1520 may include information on data transmission rate, datalength, and so on.

The HE-SIG A 1530 may also include identification information forindicating a target STA that is to receive the DL MU PPDU. For example,the HE-SIG A 1530 may include an identifier indicating whether thetransmitted PPDU is transmitted via DL transmission or UL transmission,an identifier of a specific STA (or AP) that is to receive the PPDU andinformation for indicating a group of specific STAs. Also, in case theDL MU PPDU is transmitted based on OFDMA or MIMO, the HE-SIG A 1530 mayalso include resource allocation information for the reception of the DLMU PPDU by the STA.

Additionally, the HE-SIG A 1530 may also include color bits informationfor BSS identification information, bandwidth information, transmissionopportunity (TXOP) duration information, tail bit, CRC bit, modulationand coding scheme (MCS) information on the HE-SIG B 1540, information onthe number of symbols for the HE-SIG B 1540, and cyclic prefix (CP) (orguard interval (GI)) length information.

Additionally, the HE-SIG A 1530 may have a repeat mode in order toextend the transmission range. In case the repeat mode is used in theHE-SIG A 1530, usage of the repeat mode before the HE-SIG A 1530 may beindicated. In the repeat mode, the HE-SIG A 1530 may be repeated once(or 1 time). A bit interleaver may be bypassed by a repeated HE-SIG Asymbol.

The HE-SIG B 1540 may include information on a length modulation andcoding scheme (MCS) of a physical layer service data unit (PSDU) foreach STA and a tail bit, and so on. Additionally, the HE-SIG B 1540 mayalso include information on the STA that is to receive the PPDU andresource allocation information based on OFDMA (or MU-MIMO information).In case the resource allocation information based on OFDMA (or MU-MIMOinformation) is included in the HE-SIG B 1540, the resource allocationinformation may not be included in the HE-SIG A 1530.

The fields before the HE-SIG B 1540 within the DL MU PPDU may each betransmitted from different transmission resources in a duplicatedformat. In case of the HE-SIG B 1540, the HE-SIG B 1540 beingtransmitted from part of the resource units (e.g., resource unit 1 andresource unit 2) may correspond to an independent field includingseparate information, and the HE-SIG B 1540 being transmitted from theremaining resource units (e.g., resource unit 3 and resource unit 4) maycorrespond to a duplicated format of the HE-SIG B 1540, which istransmitted from another resource unit (e.g., resource unit 1 andresource unit 2).

More specifically, the HE-SIG B 1540 may include a common block and aplurality of user blocks. The common block may include information onthe resource allocation, and the user block may include per STA specificinformation (or user specific information). A separate CRC may bedefined for the common block, and separate CRCs may be respectivelydefined for each of a predetermined number of the plurality of userblocks. For example, a case when the HE-SIG B 1540 includes 1 commonblock and 5 user blocks (user block 1 to user block 5) and when a CRCfor the user block is defined for each unit of 2 user blocks may beassumed herein. In this case, CRC1 for the common block, CRC2 for userblock 1 and user block 2, CRC3 for user block 3 and user block 4, andCRC4 for user block 5 may be included in the HE-SIG B.

Each of the plurality of block included in the HE-SIG B 1540, which istransmitted from one resource unit, may include information on aplurality of users. For example, user block 1 may include user specificinformation corresponding to STA1 and STA2, and user block 2 may includeuser specific information corresponding to STA3 and STA4.

Each of HE SIG B1 being transmitted from resource unit 1 and HE SIG B2being transmitted from resource unit 2 may correspond to a HE SIG Bincluding different types of information. For example, HE SIG B1 beingtransmitted from resource unit 1 may include common blocks and userblocks correspond to each of STA1 and STA2, and HE SIG B2 beingtransmitted from resource unit 2 may include common blocks and userblocks correspond to each of STA3 and STA4. As described above, HE SIGB1 that is transmitted from resource unit 3 may be generated byduplicating HE SIG B1, which is transmitted from resource unit 1. And,HE SIG B2 that is transmitted from resource unit 4 may be generated byduplicating HE SIG B2, which is transmitted from resource unit 2.

The HE-STF 1550 may be used for enhancing automatic gain controlestimation in a multiple input multiple output (MIMO) environment or anOFDMA environment.

More specifically, STA1 may receive HE-STF1, which is transmitted fromthe AP through resource unit 1 and may then perform synchronization,channel tracking/estimation, and AGC, thereby being capable of decodingdata field 1 (or frame 1). Similarly. STA2 may receive HE-STF2, which istransmitted from the AP through resource unit 2 and may then performsynchronization, channel tracking/estimation, and AGC, thereby beingcapable of decoding data field 2 (or frame 2). STA3 may receive HE-STF3,which is transmitted from the AP through resource unit 3 and may thenperform synchronization, channel tracking/estimation, and AGC, therebybeing capable of decoding data field 3 (or frame 3). And, STA4 mayreceive HE-STF4, which is transmitted from the AP through resource unit4 and may then perform synchronization, channel tracking/estimation, andAGC, thereby being capable of decoding data field 4 (or frame 4).

The HE-LTF 1560 may be used for estimating a channel in a MIMOenvironment or an OFDMA environment.

The inverse fast fourier transform (IFFT) size being applied to theHE-STF 1550 and the field after the HE-STF 1550 may be different fromthe IFFT size being applied to the field before the HE-STF 1550. Forexample, the IFFT size being applied to the HE-STF 1550 and the fieldafter the HE-STF 1550 may be 4 times larger than the IFFT size beingapplied to the field before the HE-STF 1550. In case the STA may receivethe HE-SIG A 1530 and may receive indication to receive a downlink PPDUbased on the HE-SIG A 1530. In this case, the STA may perform decodingbased on the HE-STF 1550 and the FFT size that is changed starting fromthe field after the HE-STF 1550. Conversely, in case the STA fails toreceive indication to receive the downlink PPDU based on the HE-SIG A1530, the STA may stop the decoding process and may perform networkallocation vector (NAV) configuration. A cyclic prefix (CP) of theHE-STF 1550 may have a size that is larger than the CP of other fields,and, during such CP period, the STA may change the FFT size and mayperform decoding on the downlink PPDU.

The access point (AP) may allocate each of the plurality of the resourceunits to each of the plurality of stations (STAs) within the entirebandwidth and may transmit individual data fields (or frames), whichcorrespond to each of the plurality of STAs, to each of the plurality ofSTAs through each of the plurality of resource units. As describedabove, the information on the allocation of each of the plurality ofresource units to each of the plurality of STAs may be included in theHE-SIG A 1550 or the HE-SIG B 1560.

FIG. 16 is a conceptual view illustrating a transmission of a UL MU PPDUaccording to an exemplary embodiment of the present invention.

Referring to FIG. 16, a plurality of STAs may transmit a UL MU PPDU tothe AP based on UL MU OFDMA.

The L-STF 1600, the L-LTF 1610, the L-SIG 1620, the HE-SIG A 1630, andthe HE-SIG B 1640 may perform the functions, which are disclosed in FIG.15. The information that is included in the signal field (L-SIG 1620,HE-SIG A 1630, and HE-SIG B 1640) may be generated based on theinformation included in the signal field of the received DL MU PPDU.

STA1 may perform uplink transmission through the entire bandwidth up toHE-SIG B 1640, and, then, STA1 may perform uplink transmission throughthe allocated bandwidth starting from HE-STF 1650. STA1 may deliver (orcarry) an uplink frame through the allocated bandwidth (e.g., resourceunit1) based on a UL MU PPDU. The AP may allocate an uplink resourcecorresponding to each of the plurality of STAs based on a DL MU PPDU(e.g., HE-SIG A/B), and each of the plurality of STAs may receive thecorresponding uplink resource and then transmit a UL MU PPDU.

FIG. 17 is a block view illustrating a wireless device to which theexemplary embodiment of the present invention can be applied.

Referring to FIG. 17, as an STA that can implement the above-describedexemplary embodiment, the wireless device may correspond to an AP 1700or a non-AP station (STA) 1750.

The AP 1700 includes a processor 1710, a memory 1720, and a radiofrequency (RF) unit 1730.

The RF unit 1730 is connected to the processor 1710, thereby beingcapable of transmitting and/or receiving radio signals.

The processor 1710 implements the functions, processes, and/or methodsproposed in the present invention. For example, the processor 1710 maybe implemented to perform the operations of the AP according to theabove-described exemplary embodiments of the present invention. Theprocessor may perform the operations of the AP, which are disclosed inthe exemplary embodiments of FIG. 1 to FIG. 16.

For example, the processor 1710 may be configured to generate a PHYlayer protocol data unit (PPDU) that is to be transmitted to a pluralityof stations (STAs) and to transmit the generated PPDU to the pluralityof STAs that is allocated within the entire frequency band.

A PPDU is transmitted from each of a plurality of resource unit groupsbeing allocated to each of the plurality of STAs, and each of theplurality of resource unit groups may include a first resource unitgroup and a second resource unit group. The first resource unit groupmay include at least one resource unit, the second resource unit groupmay include one tone design resource unit, and the tone design resourceunit may include at least one other resource unit and at least oneadditional tone unit. At least one additional tone unit may includeleftover tones that remain after allocating the at least one resourceunit and the at least one other resource unit within the entirebandwidth.

A number of the at least one additional tone unit may linearly increasein accordance with an increase in the number of the at least one otherresource unit being included in the tone design resource unit.Alternatively, the number of the at least one additional tone unit maycorrespond to a fixed value that is independent from the increase in thenumber of the at least one other resource unit being included in thetone design resource unit.

The second resource unit group including the tone design resource unitmay be allocated to one allocable location that is available for theresource allocation of the tone design resource unit, among apredetermined plurality of allocable locations that are available forthe resource allocation of the tone design resource unit, and theplurality of allocatable locations for allocating the tone designresource unit may be determined based on the location of the at leastone additional tone unit within the entire bandwidth.

The STA 1750 includes a processor 1760, a memory 1770, and a radiofrequency (RF) unit 1780.

The RF unit 1780 is connected to the processor 1760, thereby beingcapable of transmitting and/or receiving radio signals.

The processor 1760 implements the functions, processes, and/or methodsproposed in the present invention. For example, the processor 1760 maybe implemented to perform the operations of the STA according to theabove-described exemplary embodiments of the present invention. Theprocessor may perform the operations of the STA, which are disclosed inthe exemplary embodiments of FIG. 1 to FIG. 16.

For example, the processor 1760 may receive a PPDU that is transmittedfrom a first resource unit group including at least one resource unit,or the processor 1760 may receive a PPDU that is transmitted from asecond resource unit group including one tone design resource unit.

The processor 1710 and 1760 may include an application-specificintegrated circuit (ASIC), another chip set, a logical circuit, a dataprocessing device, and/or a converter converting a baseband signal and aradio signal to and from one another. The memory 1720 and 1770 mayinclude a read-only memory (ROM), a random access memory (RAM), a flashmemory, a memory card, a storage medium, and/or another storage device.The RF unit 1730 and 1780 may include one or more antennas transmittingand/or receiving radio signals.

When the exemplary embodiment is implemented as software, theabove-described method may be implemented as a module (process,function, and so on) performing the above-described functions. Themodule may be stored in the memory 1720 and 1770 and may be executed bythe processor 1710 and 1760. The memory 1720 and 1770 may be locatedinside or outside of the processor 1710 and 1760 and may be connected tothe processor 1710 and 1760 through a diversity of well-known means.

What is claimed is:
 1. A method for allocating resource units in awireless local area network (WLAN), the method comprising: generating,by an access point (AP), a physical (PHY) layer protocol data unit(PPDU) for a plurality of stations (STAs); and transmitting, by the AP,the PPDU to the plurality of STAs based on a plurality of resource unitgroups for an entire frequency bandwidth, wherein each of the pluralityof resource unit groups is allocated to each of the plurality of STAs,wherein each of the plurality of resource unit groups corresponds to atleast one 26-tone resource unit or a tone design resource unit thatincludes at least one other 26-tone resource unit and at least oneadditional tone unit, and wherein the at least one additional tone unitcorresponds to leftover tones remaining after a plurality of frequencytones corresponding to the plurality of resource unit groups are dividedin a 26-tone resource unit.
 2. The method of claim 1, wherein a numberof the at least one additional tone unit is linearly increased inaccordance with an increase in a number of the at least one other26-tone resource unit.
 3. The method of claim 2, wherein a number of theat least one additional tone unit corresponds to a fixed value beingindependent from the increase in the number of the at least one other26-tone resource unit.
 4. The method of claim 1, wherein the tone designresource unit is located to one of a predetermined plurality ofallocatable frequency locations within the entire frequency bandwidth,and wherein the predetermined plurality of allocatable frequencylocations are determined based on a location of the at least oneadditional tone unit.
 5. The method of claim 1, wherein the entirefrequency bandwidth corresponds to 20 MHz, wherein the plurality offrequency tones correspond to a 242-tone resource unit, and wherein eachof the at least one additional tone unit corresponds to a 4-toneleftover tone unit.
 6. An access point (AP) allocating resource units ina wireless local area network (WLAN), the AP comprising: a radiofrequency (RF) unit transmitting and receiving radio signals; and aprocessor being operatively connected to the RF unit, wherein theprocessor is configured: to generate a physical (PHY) layer protocoldata unit (PPDU) for a plurality of stations (STAs), and to transmit thePPDU to the plurality of STAs based on a plurality of resource unitgroups for an entire frequency bandwidth, wherein each of the pluralityof resource unit groups is allocated to each of the plurality of STAs,wherein each of the plurality of resource unit groups corresponds to atleast one 26-tone resource unit or a tone design resource unit thatincludes at least one other 26-tone resource unit and at least oneadditional tone unit, and wherein the at least one additional tone unitcorresponds to leftover tones remaining after a plurality of frequencytones corresponding to the plurality of resource unit groups are dividedin a 26-tone resource unit.
 7. The AP of claim 6, wherein a number ofthe at least one additional tone unit is linearly increased inaccordance with an increase in a number of the at least one other26-tone resource unit.
 8. The AP of claim 7, wherein a number of the atleast one additional tone unit corresponds to a fixed value beingindependent from the increase in the number of the at least one other26-tone resource unit.
 9. The AP of claim 6, wherein the tone designresource unit is located to one of a predetermined plurality ofallocatable frequency locations within the entire frequency bandwidth,and wherein the predetermined plurality of allocatable frequencylocations are determined based on a location of the at least oneadditional tone unit.
 10. The AP of claim 6, wherein the entirefrequency bandwidth corresponds to 20 MHz, wherein the plurality offrequency tones correspond to a 242-tone resource unit, and wherein eachof the at least one additional tone unit corresponds to a 4-toneleftover tone unit.